This invention relates to a therapy control system for body fluid sampling and more particularly to blood sampling apparatus and methods which operate to collect a sample of blood, to transport that sample of blood to a location remote from the site of sample collection and thereafter to dispense the blood sample such that in vitro diagnostic blood tests may be performed.
Modern medical procedures require numerous tests to be performed on blood samples in regard to clotting characteristics, blood gas concentrations, blood chemistries and various other tests. These tests are required for a patient under treatment in a hospital or other facility. In typical techniques blood is usually manually drawn from the patient's vein, artery or from tubing through which the patient's blood is circulated external to the body. The amount of blood drawn and the frequency of collection from a patient is a function of the number of tests that have to be performed. In any event, a relatively large number of blood samples are frequently required at great inconvenience to the medical staff and discomfort to the patient.
The monitoring of a hospital patient's condition, particularly those confined to intensive care or undergoing various surgical or vascular-invasive procedures, is often accomplished by means of testing blood samples collected at regular time intervals. These means usually require the use of a needle for collection of from 3 to 10 ml. of blood per test. Traditional methods of collecting and testing such blood samples are wasteful, cumbersome and time consuming. Thus, it is usual for such sampling to be limited by practical considerations to intervals of 6 to 24 hours in the clinical situation and, with considerably greater difficulty, to intervals as short as every 15 to 30 minutes in surgical and vascular-invasive procedures. The resultant data frequently misses rapidly changing physiological conditions that are of clinical significance.
It is, therefore, an object of the present invention to provide a system whereby one can repeatedly collect and transport discrete blood samples by means of various conduits or tubes to a test site or suitable container. As will be explained, the apparatus operates to direct samples of blood taken directly from a patient or in vivo reservoir. In this manner the apparatus operates to direct the blood samples to a test site or suitable container that can be remotely located from the physical location of the patient and where various tests can be performed on the samples.
It is a further object of the present invention to assure that the entire tubing and system components are automatically cleaned and flushed prior to introduction into the system of the body fluid to be tested. In this manner the entire procedure automatically transports the blood to a test site and does so without the fear of contamination of the blood samples or contamination of the patient by the apparatus or by the methods of controlling the apparatus.
It is yet a further object of the present invention to provide control of the size of the blood sample so as to meet the requirements of the test apparatus adapted to this invention and limit the waste of patient blood.
It is still a further object of the present invention to draw a sample of blood from an in vivo patient source and thereafter to maintain in an open or unclogged condition the route through which that sample is drawn.